1. Field of the Invention
The present invention relates to a resin molding apparatus that forms a molded product.
2. Description of the Background Art
Conventionally, resin molding of a molded product (for example, a substrate to which an electronic component is attached) has been performed with a resin molding apparatus (hereinafter simply referred to as “an apparatus” also).
The apparatus includes, as shown in Japanese Patent Laying-Open No. 8-207051 (page 3, FIG. 4), a top mold and a bottom mold facing the same. The top mold is attached to the bottom face of a fixing member. The bottom mold is attached to the top face of a movable member. The fixing member and the movable member are supported by a post. The fixing member is fixed to the post. The movable member is moved in the upward/downward direction along the post by a drive mechanism. Thus, the movable member moves toward or away from the fixing member. The drive mechanism has two sets of link mechanisms. The two sets of link mechanisms are connected to the bottom face of the central portion of the movable member. Accordingly, the movable member moves in the upward/downward direction by the two sets of link mechanisms bending and expanding.
In the conventional apparatus as described above, the drive mechanism pushes up the central portion of the movable member when the top and bottom molds are clamped. As a result, the bottom mold is warped upwardly in a convex manner. Thus, the bottom mold pushes up the top mold. Accordingly, the top mold and the fixing member are warped upwardly in a convex manner. Here, if the top mold deforms to be in a warped shape corresponding to the warped shape of the bottom mold, no gap is created between the top and the bottom molds. Thus, resin is molded without any resin burr.
In the conventional apparatus as described above, when a mold-opening operation and a mold-clamping operation are successively conducted, the movable member is warped upwardly in a convex manner and returned to the original state. Additionally, the movable member and the drive mechanism are rigid-joined (fixed-joined). Therefore, a connection portion between the movable member and the drive mechanism receives stress concentration, which results in a crack at that connection portion. Thus, sufficient push-up force cannot be provided from the drive mechanism to the movable member and to the bottom mold. Thus, the warped shape of the top mold and that of the bottom mold do not correspond to each other. That is, a gap is created between the top mold and the bottom mold. As a result, molten resin enters the gap. Thus, a resin burr is formed with the molded product.
The present invention is made to solve the above-described problem, and its object is to provide a resin molding apparatus wherein formation of resin burr is prevented.